City workers able to recover approximately 3,000 gallons
Just after 3:30 p.m. on Monday, April 14, a contractor working for Florida Power & Light Co. (FPL) whose crew was engaged in horizontal directional drilling struck the City of Venice’s 8-inch reclaimed water main line, causing about 83,000 gallons of reclaimed water to spill, the city reported to the Florida Department of Environmental Protection (FDEP).
Reclaimed water is sewage “that has received at least secondary treatment and basic disinfection and is reused after flowing out of a domestic wastewater treatment facility,” FDEP explains.
The incident occurred along the eastern side of the right of way of Knights Trail Road in Nokomis, the report pointed out. The exact location was approximately 200 feet south of Villoresi Boulevard, the city report noted.
One vacuum truck and two pump trucks “were used to recover as much of the spill as possible” from the site of the break, the report explained.
Pumping the reclaimed water from the site “prevented further discharge to the stormwater system,” the report said. Additionally, a small berm was constructed to contain the discharge, the report noted.
“Approximately 50,000 gallons was collected in the trucks, of which approximately 3,000 gallons came from the adjacent stormwater ditch/spill,” the report said.
“The spill volume was calculated using the volume leaving the WWTP [city’s wastewater treatment plant] minus the volume recovered from the excavation [site]” that did not enter the stormwater system, the report added.
“The volume leaving the WWTP (130,000 gallons) was calculated from the Plant SCADA system using the level in the ground storage tank, the average flow going into the tank, and the time elapsed while the reclaimed system was off,” the report pointed out. Nonetheless, it continued, some water continued to leak.
The National Institute of Standards and Technology explains that a SCADA system is a supervisory control and data acquisition system that is capable of gathering and processing data and applying operational controls over long distances. Typical uses include power transmission and distribution and pipeline systems.”
The duration of the leak was 3.5 hours, the City of Venice report said. However, the report noted, the collection of the spilled reclaimed water was completed by 4:45 p.m.
A city inspector who was on-site was notified immediately of the break in the line when it occurred, the report pointed out. Then the reclaimed system was shut down at the wastewater treatment plant, “which was approximately 1.25 miles south of the break,” the report continued. Valves were used to isolate the main pipeline.
Further, the report explained, “The delay in getting a complete shutdown of the reclaimed system” was a result of the fact that a “critical valve” had been paved over. Since the incident occurred, the report pointed out, this valve has “been uncovered and exercised. This valve would have allowed complete isolation of the break without shutting down the reclaimed system at the plant.”
The report added that city staff “is continually working on our valve maintenance and exercising program, with more attention being given to regional isolation.”
The contractor involved in the incident was identified as DBE Utility Services, which is based in Loxahatchee, its website says.